1. Field of the Invention
The present invention relates to a printing method and printing apparatus for performing printing by adjusting a print state according to a monitored result, while monitoring the print state of such a medium as a sheet of paper by using a high frequency electromagnetic wave ranging from a millimeter wave to a terahertz wave. More specifically, the present invention relates to a technique appropriate for a printing method and printing apparatus for quickly performing printing on a sheet of paper.
2. Description of the Related Art
Non-destructive examination techniques using high frequency electromagnetic waves with an arbitrary frequency band ranging from a millimeter wave to a terahertz wave (30 GHz to 30 THz) (also referred to ‘terahertz wave’ in this specification) have been developed. It is known that the terahertz waves include absorption lines for various materials including biomolecular. The frequency region is applied to an imaging technique for performing safe fluoroscopy to replace the X-ray. It is also applied to spectral techniques for examining a binding state of molecules by obtaining an absorbing spectrum or a complex dielectric constant inside an object. Techniques for analyzing biomolecular and techniques for evaluating a carrier density or movement are also candidates as an application of the newly developed techniques.
In the image forming apparatus for forming an image on a sheet of paper like a copy machine or a printer, the print state needs to be always kept equal. Generally, the print state is susceptible to a change in the printing environment both inside and outside the printing apparatus including a change in temperature or humidity. In most cases, the printing condition is adjusted and fit to the change in the printing environment in a detecting manner for detecting such a change in the printing environment. Under such printing conditions, an image is formed on a sheet of paper.
As one of the detecting manners, apparatus for measuring the coating thickness or the moisture content of ink using the terahertz wave is disclosed (Japanese Patent Application Laid-Open No. 2002-292832). The disclosed technique always monitors the coating thickness or the moisture content of ink by using a change in transmittance of the terahertz wave. Then, it controls the print state in an attempt to improve the quality of printed matters by using the monitored result.